products = [("牛奶",5),("鸡蛋",20),("香蕉",10),("杯子",10)]
shopping_list = []
money = float(input("请输入您的购物资金："))
while True:
    print("*"*30)
    print("商品列表如下：")
    for index,product in enumerate(products):
        print(f"{index+1}.商品: {product[0]}.价格: {product[1]}")
    print("*" * 30)
    option = input("请输入您要购买的商品(退出请键入q):")
    if option.isdigit():
        option = int(option)
        if 0 <= option-1 < len(products):
            option_product = products[option - 1]
            if option_product[1] <= money:
                shopping_list.append(option_product)
                money -= option_product[1]
                print("购买成功！")
            else:
                print(f"您的余额不足，余额为：{money}")
        else:
            print("您选的商品不存在！")
    elif option == "q":
        print("-" * 10,"购物清单","-" * 10)
        for item in shopping_list:
            print(f"已购商品：{item[0]},价格： {item[1]}")
        print("您的余额为：",money)
        break
    else:
        print("您的输入不合法！")
